CN1312519C - Back Light module and liquid crystal display utilizing the same back light module - Google Patents

Back Light module and liquid crystal display utilizing the same back light module Download PDF

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Publication number
CN1312519C
CN1312519C CNB031331572A CN03133157A CN1312519C CN 1312519 C CN1312519 C CN 1312519C CN B031331572 A CNB031331572 A CN B031331572A CN 03133157 A CN03133157 A CN 03133157A CN 1312519 C CN1312519 C CN 1312519C
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CN
China
Prior art keywords
lamp
backlight module
signal
lamps
low pressure
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Expired - Fee Related
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CNB031331572A
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Chinese (zh)
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CN1577004A (en
Inventor
何连任
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Darfon Electronics Corp
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Darfon Electronics Corp
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Priority to CNB031331572A priority Critical patent/CN1312519C/en
Publication of CN1577004A publication Critical patent/CN1577004A/en
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Publication of CN1312519C publication Critical patent/CN1312519C/en
Anticipated expiration legal-status Critical
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Abstract

The present invention relates to a back light module which at least comprises a plurality of lamps L1 to Ln which are arranged in parallel, each lamp is provided with a high voltage end and a low voltage end, high voltage ends and low voltage ends of odd lamps (Lm, m=1, 3, 5, etc.) are respectively arranged on a first side and a second side, high voltage ends and low voltage ends of even lamps (Lm, m=2, 4, 6, etc.) are respectively arranged on the second side and the first side, wherein high voltage ends of odd lamps and even lamps are respectively connected with first and second AC signals, and low voltage ends of the odd lamps and even lamps are respectively connected with reference grounding. The present invention also discloses a liquid crystal display which uses the back light module.

Description

Backlight module and use the LCD of this backlight module
Technical field
The present invention is relevant for a kind of backlight module, particularly relevant for a kind of backlight module that improves luminous uniformity coefficient; And openly use the LCD of described backlight module.
Background technology
Liquid crystal display (Liquid Crystal Display, hereinafter to be referred as LCD) panel more and more is used in many electronic installations, the for example display screen of mobile computer, personal digital assistant (PersonalDigital Assistant, information products such as PDA), or even space flight instrument display system has all adopted the LCD technology.The product of this class usually can use in the environment of different bright-dark degrees, has better visibility in order to make the image that is presented on the lcd screen, and the LCD display device needs one (backlight) backlight source, just a light source that is positioned at the LCD back side of panel.
Fig. 1 represents the synoptic diagram of known backlit module.As shown in the figure, high voltage current changer 10 provides a plurality of high-voltage signals to arrive by a plurality of lamp L 1-L nThe backlight module of being formed 12 is as lamp L 1-L nHigh-pressure side HV receive high-voltage signal VS, low pressure end LV is connected to one during with reference to ground connection, then lamp L 1-L nTo be lighted.
The equivalent schematic of Fig. 2 indication lamp.Because lamp L 1-L nCharacteristic identical, be illustrated at this general name lamp 14; Because the high-pressure side HV of lamp 14 is connected to high-voltage signal VS, low pressure end LV is connected to one with reference to ground connection, will produce electronics (electron) and move from right to left, when electronics moves, (for example: neon), make that lamp 14 is luminous will clash into lamp 14 gas inside.But because of the housing of backlight module is mainly metal framework, and metal frame can be connected to reference to earth terminal usually, so can produce stray capacitance C between lamp 14 and the metal frame L1-C LN, when lamp 14 length are longer, stray capacitance C L1-C LNThe more, the leakage current I that it caused CL1+ ... + I CNIt is big also can to heal, and causes the high-pressure side HV of lamp 14 brighter than low pressure end LV, makes brightness of backlight module inhomogeneous.
When the size of backlight module heals when big, then the quantity of lamp also just the more, the leakage phenomenon that stray capacitance caused that it produced is also more serious.
Summary of the invention
In view of this, fundamental purpose of the present invention is for providing a kind of backlight module, and the control stray-capacity effect makes the backlight module can uniformly light-emitting.
In addition, another object of the present invention is, utilizes described backlight module, makes that the display panel brightness of LCD is even.
For reaching described purpose, the present invention proposes a kind of backlight module, comprising: a plurality of lamp L 1-L n, arrangement parallel to each other, and each lamp L 1-L nHave a high-pressure side and low pressure end, odd number lamp L m, wherein the high-pressure side of m=1,3,5... and low pressure end are positioned over one first side and second side, even number of lamps L respectively m, wherein the high-pressure side of m=2,4,6... and low pressure end are positioned over second side and first side respectively; Wherein, the high-pressure side of odd number lamp and even number of lamps connects first and second AC signal respectively, and the low pressure end of odd number lamp and even number of lamps connects one respectively with reference to ground connection.
For reaching described another purpose, the present invention proposes a kind of LCD, comprises at least: a display panel; And described backlight module, be arranged at the back side of display panel, in order to being provided, uses light source to display panel, and make display panel be able to uniformly light-emitting.
Description of drawings
For described and other purposes of the present invention, feature and advantage can be become apparent, cited below particularlyly go out preferred embodiment, and conjunction with figs., be described in detail as follows.
Fig. 1 represents the synoptic diagram of known backlit module.
The equivalent schematic of Fig. 2 indication lamp.
Fig. 3 represents backlight module synoptic diagram of the present invention.
Fig. 4 represents backlight module first embodiment of the present invention.
The stray capacitance equivalent schematic of Fig. 5 indication lamp.
The stray capacitance equivalent schematic of Fig. 6 indication lamp.
Symbol description
10～high voltage current changer;
L 1-L n, 14～lamp;
12～backlight module;
30a, 30b～high voltage current changer.
Embodiment
Fig. 3 represents backlight module synoptic diagram of the present invention.As shown in the figure, backlight module 12 comprises: a plurality of lamp L 1-L n, wherein, each lamp L 1-L nArrangement parallel to each other, the distance between lamp is equal to each other, and each lamp L 1-L nHave a high-pressure side HV and low pressure end LV; Odd number lamp (L m, m=1,3,5...) high-pressure side HV and low pressure end LV be positioned over one first side and second side, even number of lamps (L respectively m, m=2,4,6...) high-pressure side HV and low pressure end LV be positioned over second side and first side respectively.
Wherein, the high-pressure side HV of odd number lamp connects the first AC signal AC1 that high voltage current changer 30a is sent; The high-pressure side HV of even number of lamps connects the second AC signal AC2 that high voltage current changer 30b is sent, and the low pressure end LV of odd number lamp and even number of lamps connects with reference to earth terminal respectively.
Because lamp L 1-L nStray-capacity effect, as lamp L 1-L nHigh-pressure side HV obtain AC signal, when low pressure end LV is connected to reference to ground connection because leakage phenomenon that stray capacitance caused makes that the high-pressure side HV of lamp is more and more dark to the brightness meeting of low pressure end LV, but by the present invention with lamp L 1-L nHigh-pressure side HV and low pressure end LV be staggered, then can avoid known backlit module high pressure distolateral bright especially, the distolateral dark especially shortcoming of low pressure; And, with the present invention's diffusion mould (diffuser) with light source diffusion of arranging in pairs or groups, just can be with the light source uniform distribution of backlight module.
The present invention does not limit the quantity of lamp in the backlight module, heals when big when backlight module, represents its inner lamp quantity also the more, for convenience of description for the purpose of, at this, only the backlight module of being formed with four lamps is illustrated.Fig. 4 represents backlight module first embodiment of the present invention.As shown in the figure, backlight module 12 has lamp L 1-L 4, wherein, each lamp is arranged in parallel, lamp L 1, L 3High-pressure side HV place the left side of backlight module 12, receive the first AC signal AC1 that high voltage current changer 30a is sent; Lamp L 2, L 4High-pressure side HV place the right side of backlight module 12, receive the second AC signal AC2 that high voltage current changer 30b is sent; Lamp L 1, L 3Low pressure end LV place the right side of backlight module 12, be connected to reference to earth terminal; Lamp L 2, L 4Low pressure end LV place the left side of backlight module 12, be connected to reference to earth terminal.
Lamp L 1, L 3But high-pressure side HV compensating lamp L 2, L 4The brightness of low pressure end LV; Lamp L 2, L 4But high-pressure side HV compensating lamp L 1, L 3The brightness of low pressure end LV; Make brightness of backlight module more even.
In addition, because the leakage phenomenon that stray capacitance caused of lamp and metal framework can be utilized the phase differential of controlling the first AC signal AC1 and the second AC signal AC2, to solve the problem of leakage current.Below only utilize the explanation of two lamps, illustrate how the present invention utilizes the phase differential of AC signal, solve the problem of leakage current.
The stray capacitance equivalent schematic of Fig. 5 indication lamp.As shown in the figure, having many capacitance group 51-5n between lamp, will be example with capacitance group 51 below, and the relation of each electric capacity is described.Because lamp L 1High-pressure side HV receive the first AC signal AC1 and lamp L 2Low pressure end LV be connected to reference to ground connection, so lamp L 1The voltage of high-pressure side HV greater than lamp L 2Low pressure end LV, so produce a Colaesce capacitor C 1, in addition, the metal frame of general backlight module all is connected to reference to ground connection, so capacitor C 2, C 3Represent lamp L respectively 1, L 2And the stray capacitance between metal framework.Other capacitance group by that analogy.
As lamp L 1And L 2High-pressure side HV when all receiving synchronous AC signal AC1 and AC2, lamp L 1Can produce an electric current I C1Through capacitor C 1, flow into lamp L 2, in order to increase lamp L 2Electric current, and then improve lamp L 2Brightness.Wherein, electric current I C2And I C3Be lamp L 1And L 2And the leakage current between metal framework.
Suppose, originally lamp L 1And L 2High-pressure side HV brightness be 100nits (brill: candle light), lamp L 1And L 2Low pressure end LV brightness be 80nits, work as electric current I C1Flow into L 2The time, make lamp L 1High-pressure side HV brightness be 95nits, lamp L 2Low pressure end LV brightness be 85nits, improve lamp L 2Low pressure end LV brightness, though lamp L 1High-pressure side HV brightness reduce, but overall uniformity coefficient increases substantially.
The uniformity coefficient algorithm of lamp is with the brightness of the low pressure end brightness divided by high-pressure side, when the high-pressure side of lamp and low pressure end are not staggered, lamp evenly be 80 100 = 0.8 , And after lamp was staggered, uniformity coefficient was 95 85 = 0.89 , So the present invention is the uniformity coefficient that can improve lamp.
The stray capacitance equivalent schematic of Fig. 6 indication lamp.Be lamp L with Fig. 5 difference 1Phase place and the lamp L of the first AC signal AC1 that received of high-pressure side HV 2The phase place of the second AC signal AC2 that received of high-pressure side HV anti-phase.So lamp L 2Low pressure end LV not only receive the capacitor C of flowing through 1Electric current I C1, also receive the capacitor C of flowing through 2And C 3Electric current I C2, solved the leakage phenomenon between lamp and metal framework, also make lamp L 2Low pressure end LV brightness promote.
As mentioned above, the phase place of the AC signal that control odd column lamp is received and the phase place of the AC signal that the even column lamp is received just can reach and eliminate the leakage phenomenon that stray capacitance caused; Wherein, the AC signal that received of odd column lamp can be produced or be produced by different high voltage current changers with the AC signal that the even column lamp is received by same high voltage current changer.
Backlight module of the present invention can be incorporated among any electronic product that needs back light, for example: LCD ... etc., backlight module of the present invention provides the back light of LCD panel, makes that the shown picture brightness of LCD panel is more stable.
The present invention have following some be better than known technology:
One, improves uniformity coefficient: the high-pressure side and the low pressure end of lamp are staggered, can make that the brightness between lamp is able to mutual compensation.
Two, solve leakage phenomenon: when the phase of ac signal difference that high-pressure side received of odd column and even column lamp differs 180 °, then can eliminate the leakage phenomenon between lamp and metal framework.
Though the present invention with preferred embodiment openly as above; right its is not in order to limit the present invention; any those skilled in the art; under the situation that does not break away from the spirit and scope of the present invention; can change and modification, so protection scope of the present invention is as the criterion with the claim restricted portion that is proposed.

Claims (10)

1. backlight module comprises:
A plurality of lamp L 1-L n, described lamp L 1-L nArrangement parallel to each other, and each light fixture has a high-pressure side and low pressure end, odd number lamp L m, wherein the high-pressure side of m=1,3,5... and low pressure end are positioned over one first side and second side, even number of lamps L respectively m, wherein the high-pressure side of m=2,4,6... and low pressure end are positioned over described second side and first side respectively;
Wherein, the high-pressure side of described odd number lamp and even number of lamps connects first and second AC signal respectively, and the low pressure end of described odd number lamp and even number of lamps connects one respectively with reference to ground connection.
2. backlight module as claimed in claim 1 also comprises one first driver, is arranged on described first side, in order to the high-pressure side of described first AC signal to described odd number lamp to be provided; And one second driver is arranged on described second side, in order to the high-pressure side of described second AC signal to described even number of lamps to be provided.
3. backlight module as claimed in claim 1, wherein, the distance between described lamp is identical.
4. backlight module as claimed in claim 2, wherein, described first and second AC signal is homophase each other.
5. backlight module as claimed in claim 2, wherein, described first and second AC signal is anti-phase each other.
6. LCD comprises:
One display panel; And
One backlight module is arranged at the back side of described display panel, uses to described display panel in order to light source to be provided, and comprises at least:
A plurality of lamp L 1-L n, described lamp L 1-L nArrangement parallel to each other, and each light fixture has a high-pressure side and low pressure end, odd number lamp L m, wherein the high-pressure side of m=1,3,5... and low pressure end are positioned over one first side and second side, even number of lamps L respectively m, wherein the high-pressure side of m=2,4,6... and low pressure end are positioned over described second side and first side respectively;
Wherein, the high-pressure side of described odd number lamp and even number of lamps connects first and second AC signal respectively, and the low pressure end of described odd number lamp and even number of lamps connects one respectively with reference to ground connection.
7. LCD as claimed in claim 6 also comprises one first driver, is arranged at first side of described display panel, in order to the high-pressure side of described first AC signal to described odd number lamp to be provided; And one second driver is arranged on second side of described display panel, in order to the high-pressure side of described second AC signal to described even number of lamps to be provided.
8. LCD as claimed in claim 6, wherein, the distance between described lamp is identical.
9. LCD as claimed in claim 7, wherein, described first and second AC signal is homophase each other.
10. LCD as claimed in claim 7, wherein, described first and second AC signal is anti-phase each other.
CNB031331572A 2003-07-29 2003-07-29 Back Light module and liquid crystal display utilizing the same back light module Expired - Fee Related CN1312519C (en)

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CNB031331572A CN1312519C (en) 2003-07-29 2003-07-29 Back Light module and liquid crystal display utilizing the same back light module

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Application Number Priority Date Filing Date Title
CNB031331572A CN1312519C (en) 2003-07-29 2003-07-29 Back Light module and liquid crystal display utilizing the same back light module

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CN1312519C true CN1312519C (en) 2007-04-25

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TWI440401B (en) * 2011-11-04 2014-06-01 Au Optronics Corp Lighting system having interlaced driving mechanism

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10333614A (en) * 1997-06-02 1998-12-18 Riken Light Metal Ind Co Ltd Large display device using cold-cathode fluorescent tube
JP2000352718A (en) * 1999-06-11 2000-12-19 Nec Corp Liquid crystal display device and lighting method of its back light
JP2002008408A (en) * 2000-04-15 2002-01-11 光燮 ▲チョー▼ Fluorescent lamp, backlight, and operating method for backlight
WO2003001550A2 (en) * 2001-06-25 2003-01-03 Gld Co., Ltd. External electrode fluorescent lamp, back light unit using the external electrode fluorescent lamp, lcd back light equipment using the back light unit and driving device thereof

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10333614A (en) * 1997-06-02 1998-12-18 Riken Light Metal Ind Co Ltd Large display device using cold-cathode fluorescent tube
JP2000352718A (en) * 1999-06-11 2000-12-19 Nec Corp Liquid crystal display device and lighting method of its back light
JP2002008408A (en) * 2000-04-15 2002-01-11 光燮 ▲チョー▼ Fluorescent lamp, backlight, and operating method for backlight
WO2003001550A2 (en) * 2001-06-25 2003-01-03 Gld Co., Ltd. External electrode fluorescent lamp, back light unit using the external electrode fluorescent lamp, lcd back light equipment using the back light unit and driving device thereof

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SE01 Entry into force of request for substantive examination
C14 Grant of patent or utility model
GR01 Patent grant
EE01 Entry into force of recordation of patent licensing contract

Assignee: Suzhou Darfon Electronic Co., Ltd.

Assignor: Dafang Electronics Co., Ltd.

Contract fulfillment period: 2004.4.23 to 2017.3.14 contract change

Contract record no.: 2009990000827

Denomination of invention: Back Light module and liquid crystal display utilizing the same back light module

Granted publication date: 20070425

License type: Exclusive license

Record date: 2009.7.31

LIC Patent licence contract for exploitation submitted for record

Free format text: EXCLUSIVE LICENSE; TIME LIMIT OF IMPLEMENTING CONTACT: 2004.4.23 TO 2017.3.14; CHANGE OF CONTRACT

Name of requester: SUZHOU DAFANG ELECTRONICS CO., LTD.

Effective date: 20090731

C17 Cessation of patent right
CF01 Termination of patent right due to non-payment of annual fee

Granted publication date: 20070425

Termination date: 20130729